[PATCH] Disable single thread optimization for open_memstream

[Adhemerval Zanella]

On 12/07/2017 11:10, Florian Weimer wrote:
> On 07/12/2017 04:09 PM, Szabolcs Nagy wrote:
>> Single thread optimization is valid if at thread creation time the
>> optimization can be disabled.  This is in principle true for all
>> stream objects that user code can access (and thus needs locking),
>> using the same internal list as fflush(0) uses.  However in glibc
>> open_memstream is not on that list (BZ 21735) so the optimization
>> has to be disabled.
>>
>> 2017-07-12  Szabolcs Nagy  <szabolcs.nagy@arm.com>
>>
>> 	* libio/memstream.c (__open_memstream): Set _IO_FLAGS2_NEED_LOCK.
>> 	* libio/wmemstream.c (open_wmemstream): Likewise.
> 
> What about the test case I posted?
> 
> Florian
> 

I am about to update my BZ#21735 fix based on Florian's comment, as for
this workaround it should touch only memstream implementation.